/**
 * Unobtrusive scripting adapter for jQuery
 *
 * Requires jQuery 1.6.0 or later.
 * https://github.com/rails/jquery-ujs
 * Uploading file using rails.js
 * =============================
 *
 * By default, browsers do not allow files to be uploaded via AJAX. As a result, if there are any non-blank file fields
 * in the remote form, this adapter aborts the AJAX submission and allows the form to submit through standard means.
 *
 * The `ajax:aborted:file` event allows you to bind your own handler to process the form submission however you wish.
 *
 * Ex:
 *     $('form').live('ajax:aborted:file', function(event, elements){
 *       // Implement own remote file-transfer handler here for non-blank file inputs passed in `elements`.
 *       // Returning false in this handler tells rails.js to disallow standard form submission
 *       return false;
 *     });
 *
 * The `ajax:aborted:file` event is fired when a file-type input is detected with a non-blank value.
 *
 * Third-party tools can use this hook to detect when an AJAX file upload is attempted, and then use
 * techniques like the iframe method to upload the file instead.
 *
 * Required fields in rails.js
 * ===========================
 *
 * If any blank required inputs (required="required") are detected in the remote form, the whole form submission
 * is canceled. Note that this is unlike file inputs, which still allow standard (non-AJAX) form submission.
 *
 * The `ajax:aborted:required` event allows you to bind your own handler to inform the user of blank required inputs.
 *
 * !! Note that Opera does not fire the form's submit event if there are blank required inputs, so this event may never
 *    get fired in Opera. This event is what causes other browsers to exhibit the same submit-aborting behavior.
 *
 * Ex:
 *     $('form').live('ajax:aborted:required', function(event, elements){
 *       // Returning false in this handler tells rails.js to submit the form anyway.
 *       // The blank required inputs are passed to this function in `elements`.
 *       return ! confirm("Would you like to submit the form with missing info?");
 *     });
 */

(function($, undefined) {
    // Shorthand to make it a little easier to call public rails functions from within rails.js
    var rails;

    $.rails = rails = {
        // Link elements bound by jquery-ujs
        linkClickSelector: 'a[data-confirm], a[data-method], a[data-remote]',

        // Select elements bound by jquery-ujs
        selectChangeSelector: 'select[data-remote]',

        // Form elements bound by jquery-ujs
        formSubmitSelector: 'form',

        // Form input elements bound by jquery-ujs
        formInputClickSelector: 'form input[type=submit], form input[type=image], form button[type=submit], form button:not([type])',

        // Form input elements disabled during form submission
        disableSelector: 'input[data-disable-with], button[data-disable-with], textarea[data-disable-with]',

        // Form input elements re-enabled after form submission
        enableSelector: 'input[data-disable-with]:disabled, button[data-disable-with]:disabled, textarea[data-disable-with]:disabled',

        // Form required input elements
        requiredInputSelector: 'input[name][required]:not([disabled]),textarea[name][required]:not([disabled])',

        // Form file input elements
        fileInputSelector: 'input:file',

        // Make sure that every Ajax request sends the CSRF token
        CSRFProtection: function(xhr) {
            var token = $('meta[name="csrf-token"]').attr('content');
            if (token) xhr.setRequestHeader('X-CSRF-Token', token);
        },

        // Triggers an event on an element and returns false if the event result is false
        fire: function(obj, name, data) {
            var event = $.Event(name);
            obj.trigger(event, data);
            return event.result !== false;
        },

        resolveOrReject: function(deferred, resolved) {
            if (resolved) {
                deferred.resolve();
            } else {
                deferred.reject();
            }
            return deferred;
        },

        // Default confirm dialog, may be overridden with custom confirm dialog in $.rails.confirm
        confirm: function(message) {
            var res = confirm(message),
                answer = $.Deferred();

            rails.resolveOrReject(answer, res);
            return answer.promise();
        },

        // Default ajax function, may be overridden with custom function in $.rails.ajax
        ajax: function(options) {
            return $.ajax(options);
        },

        // Submits "remote" forms and links with ajax
        handleRemote: function(element) {
            var method, url, data, button,
                crossDomain = element.data('cross-domain') || null,
                dataType = element.data('type') || ($.ajaxSettings && $.ajaxSettings.dataType),
                options;

            if (rails.fire(element, 'ajax:before')) {

                if (element.is('form')) {
                    method = element.attr('method');
                    url = element.attr('action');
                    data = element.serializeArray();
                    // memoized value from clicked submit button
                    button = element.data('ujs:submit-button');
                    if (button) {
                        data.push(button);
                        element.data('ujs:submit-button', null);
                    }
                } else if (element.is('select')) {
                    method = element.data('method');
                    url = element.data('url');
                    data = element.serialize();
                    if (element.data('params')) data = data + "&" + element.data('params');
                } else {
                    method = element.data('method');
                    url = element.attr('href');
                    data = element.data('params') || null;
                }

                options = {
                    type: method || 'GET', data: data, dataType: dataType, crossDomain: crossDomain,
                    // stopping the "ajax:beforeSend" event will cancel the ajax request
                    beforeSend: function(xhr, settings) {
                        if (settings.dataType === undefined) {
                            xhr.setRequestHeader('accept', '*/*;q=0.5, ' + settings.accepts.script);
                        }
                        return rails.fire(element, 'ajax:beforeSend', [xhr, settings]);
                    },
                    success: function(data, status, xhr) {
                        element.trigger('ajax:success', [data, status, xhr]);
                    },
                    complete: function(xhr, status) {
                        element.trigger('ajax:complete', [xhr, status]);
                    },
                    error: function(xhr, status, error) {
                        element.trigger('ajax:error', [xhr, status, error]);
                    }
                };
                // Only pass url to `ajax` options if not blank
                if (url) { options.url = url; }

                rails.ajax(options);
            }
        },

        // Handles "data-method" on links such as:
        // <a href="/users/5" data-method="delete" rel="nofollow" data-confirm="Are you sure?">Delete</a>
        handleMethod: function(link) {
            var href = link.attr('href'),
                method = link.data('method') || 'GET',
                csrf_token = $('meta[name=csrf-token]').attr('content'),
                csrf_param = $('meta[name=csrf-param]').attr('content'),
                form = $('<form></form>', { action: href, method: method, 'data-ujs-generated': 'true' }),
                metadata_input = '';

            if (method !== 'GET') {
                form.attr('method', 'POST');
                metadata_input += '<input name="_method" value="' + method + '" type="hidden" />';

                if (csrf_param !== undefined && csrf_token !== undefined) {
                    metadata_input += '<input name="' + csrf_param + '" value="' + csrf_token + '" type="hidden" />';
                }
            }

            form.hide().append(metadata_input).appendTo('body');
            form.submit();
        },

        /* Disables form elements:
         - Caches element value in 'ujs:enable-with' data store
         - Replaces element text with value of 'data-disable-with' attribute
         - Adds disabled=disabled attribute
         */
        disableFormElements: function(form) {
            form.find(rails.disableSelector).each(function() {
                var element = $(this),
                    method = element.is('button') ? 'html' : 'val';

                element.data('ujs:enable-with', element[method]());
                element[method](element.data('disable-with'));
                element.attr('disabled', 'disabled');
            });
        },

        /* Re-enables disabled form elements:
         - Replaces element text with cached value from 'ujs:enable-with' data store (created in `disableFormElements`)
         - Removes disabled attribute
         */
        enableFormElements: function(form) {
            form.find(rails.enableSelector).each(function() {
                var element = $(this),
                    method = element.is('button') ? 'html' : 'val';

                if (element.data('ujs:enable-with')) element[method](element.data('ujs:enable-with'));
                element.removeAttr('disabled');
            });
        },

        /* For 'data-confirm' attribute:
         - Fires `confirm` event
         - Shows the confirmation dialog
         - Fires the `confirm:complete` event
         Returns `true` if no function stops the chain and user chose yes; `false` otherwise.
         Attaching a handler to the element's `confirm` event that returns a `falsy` value cancels the confirmation dialog.
         Attaching a handler to the element's `confirm:complete` event that returns a `falsy` value makes this function
         return false. The `confirm:complete` event is fired whether or not the user answered true or false to the dialog.
         */
        allowAction: function(element) {
            var message = element.data('confirm'),
                confirmAnswer,
                answer = $.Deferred();

            if (!message) { return $.when(true); }

            if (rails.fire(element, 'confirm')) {
                confirmAnswer = rails.confirm(message);
                confirmAnswer.then(
                    function() {
                        var callbackOk = rails.fire(element, 'confirm:complete', [ true ]);
                        rails.resolveOrReject(answer, callbackOk);
                    },
                    function() {
                        rails.fire(element, 'confirm:complete', [ false ]);
                        answer.reject();
                    }
                );
                return answer.promise();
                // If `confirm` event handler returned false...
            } else {
                answer.reject();
                return answer.promise();
            }
        },

        // Helper function which checks for blank inputs in a form that match the specified CSS selector
        blankInputs: function(form, specifiedSelector, nonBlank) {
            var inputs = $(), input,
                selector = specifiedSelector || 'input,textarea';

            form.find(selector).each(function() {
                input = $(this);
                // Collect non-blank inputs if nonBlank option is true, otherwise, collect blank inputs
                if (nonBlank ? input.val() : !input.val()) {
                    inputs = inputs.add(input);
                }
            });
            return inputs.length ? inputs : false;
        },

        // Helper function which checks for non-blank inputs in a form that match the specified CSS selector
        nonBlankInputs: function(form, specifiedSelector) {
            return rails.blankInputs(form, specifiedSelector, true); // true specifies nonBlank
        },

        // Helper function, needed to provide consistent behavior in IE
        stopEverything: function(e) {
            $(e.target).trigger('ujs:everythingStopped');
            e.stopImmediatePropagation();
            return false;
        },

        // find all the submit events directly bound to the form and
        // manually invoke them. If anyone returns false then stop the loop
        callFormSubmitBindings: function(form) {
            var events = form.data('events'), continuePropagation = true;

            if (events !== undefined && events['submit'] !== undefined) {
                $.each(events['submit'], function(i, obj){
                    if (typeof obj.handler === 'function') return continuePropagation = obj.handler(obj.data);
                });
            }
            return continuePropagation;
        }
    };

    $.ajaxPrefilter(function(options, originalOptions, xhr){ if ( !options.crossDomain ) { rails.CSRFProtection(xhr); }});

    $(rails.linkClickSelector).live('click.rails', function(e) {
        var link = $(this);

        rails.allowAction(link).then(
            function() {
                if (link.data('remote') !== undefined) {
                    rails.handleRemote(link);
                } else {
                    rails.handleMethod(link);
                }
            },
            function() {
                rails.stopEverything(e);
            }
        );

        e.preventDefault();
    });

    $(rails.selectChangeSelector).live('change.rails', function(e) {
        var link = $(this);

        rails.allowAction(link).then(
            function() {
                rails.handleRemote(link);
            },
            function() {
                rails.stopEverything(e);
            }
        );

        e.preventDefault();
    });

    $(rails.formSubmitSelector).live('submit.rails', function(e) {
        var form = $(this),
            remote = (form.data('remote') !== undefined),
            blankRequiredInputs = rails.blankInputs(form, rails.requiredInputSelector),
            nonBlankFileInputs = rails.nonBlankInputs(form, rails.fileInputSelector);

        rails.allowAction(form).then(
            function() {
                // skip other logic when required values are missing or file upload is present
                if (blankRequiredInputs && form.attr("novalidate") == undefined && rails.fire(form, 'ajax:aborted:required', [blankRequiredInputs])) {
                    return rails.stopEverything(e);
                }

                if (remote) {
                    if (nonBlankFileInputs) {
                        return rails.fire(form, 'ajax:aborted:file', [nonBlankFileInputs]);
                    }

                    // If browser does not support submit bubbling, then this live-binding will be called before direct
                    // bindings. Therefore, we should directly call any direct bindings before remotely submitting form.
                    if (!$.support.submitBubbles && rails.callFormSubmitBindings(form) === false) return rails.stopEverything(e);

                    rails.handleRemote(form);
                } else {
                    // slight timeout so that the submit button gets properly serialized
                    setTimeout(function() {
                        rails.disableFormElements(form);
                        // Submit the form from dom-level js (i.e. *not* via jquery),
                        // which will skip all submit bindings (including this live-binding),
                        // since they have already been called.
                        form.get(0).submit();
                    }, 13);
                }
            },
            function() {
                rails.stopEverything(e);
            }
        );

        e.preventDefault();
    });

    $(rails.formInputClickSelector).live('click.rails', function(event) {
        var button = $(this);

        rails.allowAction(button).then(
            function() {
                // register the pressed submit button
                var name = button.attr('name'), form,
                    data = name ? {name:name, value:button.val()} : null;

                form = button.closest('form');
                form.data('ujs:submit-button', data);
                form.submit();
            },
            function() {
                rails.stopEverything(event);
            }
        );

        event.preventDefault();
    });

    $(rails.formSubmitSelector).live('ajax:beforeSend.rails', function(event) {
        if (this == event.target) rails.disableFormElements($(this));
    });

    $(rails.formSubmitSelector).live('ajax:complete.rails', function(event) {
        if (this == event.target) rails.enableFormElements($(this));
    });

})( jQuery );
